1. Field of the Invention
The invention relates to a workpiece with a tribologically useable surface which is formed as a sliding surface or slide face lubricated by means of an intermediate material for a counterpart moving relative thereto, wherein the slide face is provided with a structure or texture comprised of a plurality of pockets. The invention further relates to a method for producing a tribologically useable surface, in particular, a piston sliding surface or piston slide face, of a cylinder.
2. Description of the Related Art
The piston slide face or piston sliding surface in internal combustion engines and the surfaces of greatly stressed slide bearings are embodied as tribologically useable surfaces. In this connection, it is important that under all operating conditions a sufficient lubrication is ensured by an oil film and the friction of the parts moving relative to one another is maintained at a minimal level.
WO 98/14710 describes a method for configuring workpiece surfaces of a bearing, wherein the supporting bearing surface is provided with micropores which have a depth between 2 μm and 10 μm. Such micropores are generated, for example, by laser beams.
The German patent document 198 33 646 C1 describes a cylinder sliding surface of a cylinder bore in an internal combustion engine; this sliding surface is provided by honing with a crossed scoring structure. In order to ensure in a simple way lubrication of the piston in the cylinder bore during motor operation in any movement phase, the sliding surface of the cylinder is provided with oil lubrication pockets. In the area of the upper dead center of a reciprocating piston guided in the cylinder bore as well as in the area of inlet/outlet bores provided in the sliding surface, these oil lubrication pockets overlie the crossed scoring structure. Accordingly, the oil lubrication pockets have a transition into one another.
In German patent document 196 14 328 A1, a method for coating and/or material-removing machining of pre-treated workpiece surfaces is described. In this method, a preparative surface treatment is provided in order to improve adhesion of the applied layer or the material-removing machining. Instead of conventional mechanical or electrochemical roughening of the workpiece surface known for this purpose, a treatment by laser beams is provided; this treatment provides the surface with a texture or structure of a regular pattern. The pattern can be optimally matched to the desired final treatment.
The British patent document 2 340 547 A discloses a cylinder for a diesel engine; the cylinder has pockets within the inner cylinder wall in the area of the upper dead center. These pockets are arranged in a staggered arrangement relative to one another in the axial direction as well as the circumferential direction.